Woodward, OK rainwater: 20,307 gallons off a roof
How much rain a roof in Woodward, OK collects
20,307gallons a year
That is a 1,500 sq ft asphalt roof under Woodward, OK's normal 25.6 inches of rain, about 795 gallons for every inch that falls.
In Woodward, OK a single barrel does most of the work. Storms come often enough that a small tank refills before it runs dry, and a bigger one would mostly sit full.
Rainfall: NOAA 1991-2020 climate normals, the Woodward station (1.7 mi away). Woodward, OK ranks 44th wettest of the 45 cities covered in Oklahoma.
Month by month in Woodward
| Month | Rain (in) | Off the roof (gal) | Garden shortfall (gal) |
|---|---|---|---|
| Jan | 0.99 | 787 | |
| Feb | 0.84 | 668 | |
| Mar | 1.78 | 1,415 | |
| Apr | 2.20 | 1,749 | 268 |
| May | 3.97 | 3,155 | 47 |
| Jun | 3.85 | 3,060 | 62 |
| Jul | 2.41 | 1,915 | 242 |
| Aug | 2.86 | 2,273 | 186 |
| Sep | 1.73 | 1,375 | 327 |
| Oct | 2.65 | 2,106 | 212 |
| Nov | 1.08 | 858 | |
| Dec | 1.19 | 946 |
May is the wettest month (3.97 in, 3,155 gal off the roof); Feb the driest (0.84 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.
Which tank size is worth it in Woodward
Best fit: 2 linked 55-gallon barrels, which delivers about 1,176 gallons to the garden in a normal year (87.5% of its need).
If you set one up, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Woodward's roof water will pass straight through it.
| Tank | Water used (gal/yr) | Spills over (gal/yr) |
|---|---|---|
| 55 gal | 1,022 | 18,671 |
| 110 gal | 1,176 | 18,516 |
| 165 gal | 1,176 | 18,516 |
| 275 gal | 1,176 | 18,516 |
| 550 gal | 1,176 | 18,516 |
| 1,000 gal | 1,176 | 18,516 |
| 1,500 gal | 1,176 | 18,516 |
| 2,500 gal | 1,176 | 18,516 |
| 5,000 gal | 1,176 | 18,516 |
Simulated storm by storm through a normal year using the station's count of days with 0.1 in or more of rain each month.
Is rainwater collection legal in Oklahoma?
Encouraged through state legislation: Water for 2060 Act
From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source